• The first use of salt applied onto roads was in 1938 in New Hampshire.
  • Today, between 10 and 20 million tons of salt are used on roads.


  • Road salt is sodium chloride (NaCl) and is often called rock salt.
  • The US Environmental Protection Agency (EPA) set limits on the amount of chloride (Cl) allowed in water.
  • Sodium (Na) is a primary concern for human health and the EPA has set no limits on the levels of sodium allowed in water.
  • Today, we use between 10 and 20 million tons of salt on our roads.


  • An average American consumes 4,000 to 6,000 mg of sodium per day, mostly from food.
  • A study done in 2008 showed the average well water concentration in the Dutchess County is 48 mg/L of sodium. (8 cups of water yields an intake of 96 mg of sodium)
  • In this study, they found a well that contained 347 mg/L (the highest sodium concentration measured).
  • Salts have a “legacy effect” in our environment, this means that salts accumulate and stay in our environment even after salts are discarded or applied.
  • How much salt we have in our environment now (48 mg/L of sodium) could increase in the future because of the “legacy effect.”


All information via Cary Institute.

To learn more visit the Cary Institute’s information on salts.